html, body {
  width: 100%;
  height: 100%;
}

body {
  min-width: 1500px;
  display: flex;
  flex-direction: column;
}

.header {
  height: 80px;
  background-color: skyblue;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 40px;
  color: #fff;
  font-weight: 700;
  position: relative;
  border-bottom: 2px solid #333;
}

h1 {
  width: 150px;
  height: 50px;
  line-height: 50px;
  text-align: center;
  margin: 50px auto;
  background-color: #333;
  color: gold;
  border-radius: 5px;
}